***************************************************************************
**
**                               uel_vcct.for   
***************************************************************************
      SUBROUTINE UEL(RHS,AMATRX,SVARS,ENERGY,NDOFEL,NRHS,NSVARS,PROPS,
     1 NPROPS,COORDS,MCRD,NNODE,U,DU,V,A,JTYPE,TIME,DTIME,KSTEP,KINC,
     2 JELEM,PARAMS,NDLOAD,JDLTYP,ADLMAG,PREDEF,NPREDF,LFLAGS,
     3 MLVARX,DDLMAG,MDLOAD,PNEWDT,JPROPS,NJPROP,PERIOD)
C     
      INCLUDE 'ABA_PARAM.INC'
C
      DIMENSION RHS(MLVARX,*),AMATRX(NDOFEL,NDOFEL),SVARS(NSVARS),
     1 ENERGY(8),PROPS(*),COORDS(MCRD,NNODE),
     2 U(NDOFEL),DU(MLVARX,*),V(NDOFEL),A(NDOFEL),TIME(2),
     3 PARAMS(3),JDLTYP(MDLOAD,*),ADLMAG(MDLOAD,*),
     4 DDLMAG(MDLOAD,*),PREDEF(2,NPREDF,NNODE),LFLAGS(*),JPROPS(*)
C
      DIMENSION FORCE(4)
C
      DO 10 K1=1,4
      RHS(K1,NRHS)=0.D0
      DO 10 K2=1,4
      AMATRX(K2,K1)=0.D0
   10 CONTINUE                                           
C
      STX =PROPS(1)
      STY =PROPS(2)
      BBB =PROPS(3)
C
      AMATRX(1,1)= STX
      AMATRX(1,3)=-STX
      AMATRX(2,2)= STY
      AMATRX(2,4)=-STY
      AMATRX(3,1)=-STX
      AMATRX(3,3)= STX
      AMATRX(4,2)=-STY
      AMATRX(4,4)= STY
C
      DO 25 K1=1,4
      FORCE(K1)=0.D0
      DO 20 K2=1,4
      FORCE(K1)=FORCE(K1)+AMATRX(K1,K2)*U(K2)          
   20 CONTINUE                                  
      RHS(K1,1)=RHS(K1,1)-FORCE(K1)
   25 CONTINUE                                
C
      FX12=(U(1)-U(3))*STX
      FY12=(U(2)-U(4))*STY
C
      DU34=U(5)-U(7)
      DV34=U(6)-U(8)
C
      DA=ABS(COORDS(1,5)-COORDS(1,1))
C
      G1=FY12*DV34/2.0/BBB/DA
      G2=FX12*DU34/2.0/BBB/DA
C
      SVARS(1)=G1
      SVARS(2)=G2
C
      RETURN
      END